The U.K. said it would deploy tanks and drones alongside 800 troops in Eastern Europe, the first of several expected moves by the North Atlantic Treaty Organization to help counter growing fears about Russia in the region.

The U.K. troops will deploy in the spring and will be joined in Estonia by forces from France and Denmark, said Michael Fallon, the British defense secretary. The force, he said, would likely include tactical drones, Challenger 2 main battle tanks, and Warrior armored infantry fighting vehicles. "That battalion will be defensive in nature, but it will be fully combat-capable," he said in an interview.

Canada, Germany, and the U.S. are also expected to release details of their planned NATO deployments when alliance defense officials gather Wednesday to discuss strengthening their defenses against Russia. Britain had previously committed to deploying a battle group but hadn't said precisely how many troops it would send or what kind of weaponry they would be equipped with.